Telephonic apparatus.



Patented Feb. 1, 1916 .H. SMITH.

TELEPHONIC APPARATUS.

APPLICATION FILED no". 14, 19 1,170,356.

carbon granules HABALD SMITH, 0F COPENHAGEN, DENMARK, ASSIGNOR TO GEORGE KIORBOE, 0F

COPENHAGEN, DENMARK.

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Specification of Letters Patent.

Application filed November 14, 1914. Serial No. 872,087.

To all whom it may concern:

Be it known that I, HARALD $MrrH, a subject of the King of Denmark, residing at Denmark, have invented certain new and useful Improvements in Telephonic Apparatus, ofwhich the following is a specification.

This invention relates to transmitters, m1- crophones, relays and other apparatus for telephonic and similar purposes.

More particularly,

rises carbon granules, or similar conducting material of high resistance, in cooperation with a diaphragm of carbon or thelike, a fixed contact and a resilient element with the'provision of a main chamber and suitable reserve chamber or chambers whereby.

the contact areas at the diaphragm and the fixed contact are maintained uniform during the operation of the device, without affecting the sensitiveness of the diaphragm.

A usual form of my invention may be described with reference to a telephone transmitter comprising a carbon diaphragm mounted on suitable insulating material to permit proper vibrationof the diaphragm. The fixed contact, which may be of carbon or the like, insulating material toprovide for suitable main and reserve chambers in which the car bon granules are placed. The quantity of chamber and certain of the reserve chambers and the resilient element in the form of a coiled spring operates to eiiectually main-- tain the main chamber filled with carbon ules into and out of granules. Upon speaking through the mouth tube, the carbon diaphragm will be vibrated, accordingly causing corresponding inflow and outflow of thecarbongranreserve chambers, whereby the main chamber will be continuously filled with carbon granules and thereby maintain the contact areas of'the' diaphragm and the fixed contact substantially constant. As a result, the,

electrical spea g currents will be determined substantially solely by the variations of the contact pressure of the carbon granules. a

V In accordance with my invention, buz- Zing and other distortions of speech are entirely eliminated by reason of the eliminaules away from the diaphragm with consemy invention coming drawings, in whichadjacent the rear face of the insulating is supported on said 7 is suificient to fill the main all or certain of the quent variation in the contact area of the carbon granules with the diaphragm, such Patented Fee. a, acre.

the vibratory movements of the diaphragm. Other features and objects of my invention will be more fully understood from the following description and the accompany Figure 1 1s a vertical sectional view of-a telephone transmitter embodying my inven tion; and Fig. 2 is a diagrammatic vertical sectional elevation of a relay element constructed in accordance with my invention.

Referring to Fig. 1, the speaking tube 1 is of usual construction and mounted on the usual casing 2. The disk 3 of insulating material is supported by the casing 2. The diaphragm 4 of carbon is positioned on the insulating material 3 by means of the ring 5 and is connected at contact 6 with the The fixed contact 8 is disposed 7 disk 3. The eiiective contact area of fixed contact 8 'is determined by the annular projecconductor 7 tion 9 extending from the insulating disk 3 within the central opening thereof. The ring 10 of felt or the like, preferably rectangular in cross section, is positioned to the rear of the rear face of diaphragm 4 and projects within the opening of insulating disk 3'. The outer diameter of the ring 10 is slightly less than the diameter of the opening of disk 3 to avoid frictional interference wlth-the sides of said opening.

The above mentioned parts provide for the. main chamber 11 extending from the fixed contact 8 to the diaphragm 4 and of a width determined by the inner diameter of the ring 10 and the inner diameter of the annular portion 9. There is also provided a reserve chamber 12 disposed laterally of such main chamber and positioned between the annular portion 8 and the felt ring 10. Such reserve chamber 12, in the instance illustrated in Fig. 1, is annular in formation. The carbon granules 12 are in sufiicient quantity to completely fill thenlain chamber 11 and to completely fill the lower and side portions of the reserve chamber 12 and partially fill the upper portion of reserve chamber 12, when the diaphragm 4 is in normal position, as indicated in Fig. 1. The spiral spring 14 is positioned within the reserve chamber 12. The fixed contact 8 is connected to the remaining conductor 15 of the line. Upon speaking through the speaking tube 1, the diaphragm 4 Will be correspondingly set in vibration, causing the carbon granules between the diaphragm 4 and fixed contact 8 to be subjected to corresponding vibration I in contact pressure. However, the surplus carbon granules within the reserve chamber 12 under action-of the spring 14 will maintain the main chamber 11 completely filled with carbon granules and effect substantially constant contact' areas of the carbon granules at the diaphragm 4 and the fixed contact 8. The

spring 14 also functions to keep the felt ring 10 in vibratory movement corresponding to the vibratory movement of the diaphragm.

A The spring-14 may be of any suitable re-,

' silient material, such as brass or the like,

and is preferably provided with a non-corroding surface, as by gold-plating, etc.

tIt will be'noted that in accordance with my invention, the carbon granules in the im mediate vicinity of the diaphragm are precluded from undue rebound, even though soundwaves of relatively great intensity be projected against the diaphragm. By reason of the variation of the contact pressure of the carbon-granules solely determining the resulting electrical speaking currents, buzzing and. all other distortions are precluded, and the overtones and-characteristic.

harmonics of the original sound waves are transmitted to and emitted by the receiver at the receiving end of the line.

Fig. 2 indicates a relay element comprismg an electro-responsive device such as the coil 20 controlled by the transmitting instrument to which it is connected by wires 21, 22. Such coil 20 controls the movement of the diaphragm 4: through the intermediation of the armature 23 afiixed tov the front face of diaphragm 4. v Q

The conductors 24, 25, are respectively connected to the diaphragm 4 and fixed contact8 and extend to the receiving station of the line. p

The operation of the several parts of the relay element will be understood from the descrlptlon set forth hereinbefore in connection with Fig. 1.

In similar manner, my invention is applicable for micro-telephones and other telephonic purposes.

The specific embodiments hereinbefore set forth are articul'arly adaptable for use in' a vertical p ane, that is to say,'for such use where the carbon diaphragm is stationary or rotated 1n substantially the vertical plane. In such use, it will be noted that the annular reserve chamber is of especial advantage to perform its functions irrespective of the extent to which the device has been turned in the vertical plane. Y

Whereas I have described my invention by reference to specific forms thereof, it will be understood that many changes and modifications may be made without departing from the, spirit of my invention.

What I claim and desire to secure by Letters Patent is 1. In apparatus of the character described, the combination with a vibratable diaphragm and mounting means therefor, of a contact, means forming a main chamber extending from said contact to said diaphragm, means including a movable wall of insulating material on the side toward said diaphragm forming a reserve chamber communicating with said main chamber at points distant from said contact and said diaphragm and carbon granules completely filling said main chamber and at least partially filling said reserve chamber when said diaphragm is. in normal position.

2. In apparatus of the character described, the combination with a vibratable diaphragm and mounting means therefor, of a fixed contact, means forming a main chamber'extending from said diaphragm to said fixed contact, means including a movable wall of insulating material onthe side toward said diaphragm forming a reserve chamber communicating with said main chamber -at points remote from said dia-- phragm and said fixed contact and carbon granules completely filling said main chamber and at least partially filling said reserve chamber.

3. In apparatus of the character described, the combination with a vibratable diaphragm and mounting means therefor, of

a fixed contact, means forming a main chamber of substantially equal breadth and height extending from said diaphragm to said fixed contact, means including a movable wall of insulating material on the slde toward said diaphragm forming a reserve chamber communicating with. said main chamber at points distant from said diaphragm and said fixed contact, a portion of said reserve chamber being disposed above said main chamber and carbon granules completely filling said main chamber and at least partially filling said upper portion of chamber and at least partially fillingsaid reserve chamber, and resilient means for normally tending to cause carbon granules to move out of said reserve chamber and into said main chamber.

5. In apparatus of the character described, the combination With a diaphragm and mounting means therefor, of a fixed contact, means forming a main chamber extending from said diaphragm to said fixed con tact, means forming a reserve chamber communicating with said main chamber at points distant from said diaphragm and said fixed contact, carbon granules completely filling said main chamber and at least partially filling said reserve chamber and a spring disposed in said reserve chamber nor mally tending to cause said carbon granules .to move out of said reserve chamber and into said main chamber.

6. In apparatus of the character described, the combination of a diaphragm, a fixed contact, -means for supporting said fixed contact, said means comprising a block of insulating material having an opening therein and portions of said insulating material projecting within said opening in intermediate proximity to said fixed contact, an annulus of non-conducting material carried by said diaphragm and projecting within said opening a distance less than the distance between said diaphragm and said projecting portions of the insulating material, thereby forming a main chamber bounded by said diaphragm and said fixed contact, and a reserve chamber positioned between said annulus and said projecting portions of the insulating material, carbon .granules completely filling said main chamber and at least partially filling said reserve chamber and a coiled spring disposed within said reserve chamber.

7. In apparatus of the character described, the combination with a vertically disposed vibratable diaphragm, of mounting means therefor, of a contact, means forming a main chamber extending from said contact to said diaphragm, means including a movable wall of insulating material on the side toward said diaphragm forming an annular reserve chamber disposed in a vertical plane about said main chamber and communicating with said chamber at points distant from said diaphragm and said contact and carbon granules completely filling said main chamber and at least partially filling said annular reserve chamber.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

HARALD SMITH.

Witnesses: G. Klomson,

HENRY J. LUoKE, 

